Cover fastening device



H. L. MEKELBURG COVER FASTENING DEVICE May 6, 1947.

Filed Nov. 3, 1944 ammwxmwdkw Wf/NM I WW Patented May 6, 1947.

ZAZOJM CGVER FASTENENG DEVICE Harold L. Mekelburg,

Milwaukee, WiS'., assignor to (Butler-Hammer, line, Milwaukee, Wis, a corporation of Delaware Application November 3, 1944', Serial No. 561,787

. 3 Claims.

This invention relates to enclosing casings for electrical control apparatus such as drum controllers and more particularly to cover fastening devices therefor.

Drum controllers are usually provided with an enclosing casing consisting of a rear casing section and a removable U-shaped front cover mem her which fits over the back and end walls on the rear casing section to provide a complete enclosure for the contact mechanism of the controller. Heretofore the cover member was usually secured to the rear casing section by means of eye bolts located on the exterior of the enclosing casing. However, this type of securing means has been found objectionable for various reasons, as for example, the same increases the overall dimensions of the controller and is not satisfactory from the standpoint of modern streamline design.

The present invention has among its objects to provide an improved cover securing mechanism for controllers of the aforesaid type which overcomes the aforementioned objections.

Another object is to provide a concealed cover securing means for controllers of the aforesaid type which is exceedingly simple, rugged, and inexpensive in construction and which provides a spring holding force for maintaining the cover member in tight engagement with the back and end walls of the rear casing section.

Various other objects and advantages of the invention will hereinafter appear.

The accompanying drawing illustrates an embodiment of the invention which will now be described, it being understood that the embodiment illustrated is susceptible of modification without departing from the spirit and scope of theappended claims.

In the drawing,

Figure 1 is a perspective view of a drum controller casing embodying the invention, the front cover of the casing being shown detached from the rear section thereof.

Fig. 2 is a transverse sectional View of the enclosing casing shown in Fig. 1. illustrating one side of the cover in attached position and the other in a loosened position, and

Fig. 3 is a fragmentary sectional view on line 3-3 of Fig. 2.

Referring to Fig. l, the same illustrates an enclosing casing of the type commonly employed in drum controllers, including a rear casing section I and a front cover 2. The rear casing section I is provided with a rectangular back plate 3 having forwardly extending rectangular end walls 3- 3 formed on opposite ends thereof; Cover 2 comprises a U-shaped sheet metal member which is formed to fit over the end walls 4 and to straddle the back plate 3 The front and side walls of cover 2 are provided with inwardly bent end portionsii (Fig. 3) and as shown in Fig. l, the side walls of said cover are normally disposed in diverging relation to require springing thereof toward each other for engagement with the side edges of end walls 3 and back plate 3;

In the embodiment illustrated, the front and side walls of cover 2 are provided with end strip gaskets 6 (Fig, 3) for engaging the front and side edges of end walls i and the side walls are also provided with strip gaskets 7" (Fig. 2)

for'engaging the side edges of back plate 3. These gaskets are cemented to the inner face of cover 2 and areusually formed of felt for'dust-proofing of the casing or of rubber for water-proofing thereof. However; the gaskets may be omittedwhere it is' unnecessary to protect against dust or water. As shown in Fig. 3the inwardly bent portionsfi on. opposite ends of cover 2- serve asabutments for the end strip gaskets fiand each of the side strip gaskets 7' has a sheet metal retaining strip 8 associated therewith, which is secured to the cover by spot welding.

As will now be set forth, the side walls of cover 2 are provided with fastening devices 9 which.

act in applied fastening positionv to exert a spring holding force on said cover for maintaining the-same inv tight engagement with the side edges of back plate 3 and alsowith. the front and side edges of end walls i. In" the embodiment illustrated each of the sidewalls of cover 2 is provided with a single fastening device 9:

which is located midway between theends-thereof, but, as is apparent, eachside wall may be provided with a plurality of fastening devices if desired.

Each of the fastening devices 9 consists of a screw l0 and an associated screw-receiving bracket I 5 formed from a resilient sheet metal strip which is bent to provide arms l2 and I3 which are disposed in oblique angular relation, the former arm constituting a base portion and the latter having a tapped screw-receiving portion It on the free end thereof. The base portions it of brackets H are secured to the front face of back plate 3 either by welding or by means of rivets and as shown in Fig. 2 the arms I3 of said brackets extend forwardly from said back plate and toward opposite sides thereof. Also as shown on the right-hand side of Fig. 2, the brackets l I are located with respect to the a side edges of back plate 3 so that the screwreceivin portions I4 thereof are normally spaced inwardly a short distance with respect to said edges. The screws I!) are insertable through openings [5 in the side walls of cover 2 for engagement within the tapped openings in the portions M of brackets II and the outer ends of said screws are provided with slotted heads [6 for engaging said walls on the outer side thereof.

When cover 2 is placed upon the rear casing section I with the front wall thereof in engagement with the front edges of end walls 4, screws 10 will register with the tapped openings in the portions M of brackets H when the same are inserted through the openings in the side walls of said covers. As hereinbefore stated the side walls of cover 2 are normally disposed in diverging relation to require springing thereof toward each other for engagement with the side edges of back plate 3 and end walls 4. When screws I0 are screwed into the portions M of brackets H the side walls of cover 2 are drawn toward each other for engagement with the side edges of back plate 3 and end walls 4 and upon tightening of said screws the arms l3 of said brackets are deflected out of the normal position illustrated on the right-hand side of Fig. 2 into the position illustrated on the left-hand side of this figure. This deflection of the brackets l I subjects the screws [0 to a spring force which tends to move the same axially and also laterally toward the back plate 3 whereby cover 2 is held in firm engagement not only with the side edges of back plate 3 and end walls 4 but also with the front edges of said end walls.

What I claim as new and desire to secure by Letters Patent is:

1. The combination with a rear casing section having a rear wall and forwardly extending end walls, a U-shaped cover formed to fit over said end walls and to straddle the side edges of said rear wall and securing means for said cover comprising resilient brackets secured to said rear wall and having screw-receiving arms extending forwardly and toward opposite sides of said rear wall, and securing screws associated with said brackets and extending through openings in the side walls of said cover, the screw-receiving arms of said brackets being deflected when said screws are in applied fastening position to exert a spring-holding force on said cover for holding the side walls thereof in firm engagement with the side edges of said rear wall and said end walls, for also holding the front wall of said cover in firm engagement with the front edges of said end walls. I

2. The combination with a rear casing section having a rear wall and forwardly extending end walls, a U-shaped front cover to fit over the front and side edges of the end walls of said rear casing section and to straddle the rear wall thereof, and securing means for said cover comprising screws extending through openings in the side walls of said cover and brackets secured to the rear wall of said casing, each having a forwardly extending resilient arm provided with a tapped opening for receiving one of said screws, said resilient arms being normally spaced inwardly with respect to the side edges of said rear wall and being deflected outwardly with respect thereto upon tightening of their associated screws to draw the side walls of said cover inwardly and rearwardly with respect to said rear casing section for tight engagement of said cover with the front and side edges of said rear casing section.

3. The combination with a rear casing section having a rear wall and forwardly extending end walls, a U-shaped cover formed to fit over the front and side edges of the end walls of said rear casing section and to straddle the rear wall thereof, the side walls of said cover being normally disposed in diverging relation to require springing thereof toward each other for engagement with the side edges of said rear casing section, and securing means for said cover comprising screws extending through openings in the side walls of said cover and brackets secured to the rear wall of said casing section each having a forwardly extending resilient arm provided with a tapped opening for receiving one of said screws, said resilient arms being normally spaced inwardly with respect to the side edges of said rear wall and being deflected outwardly with respect thereto upon tightening of said screws to draw the side walls of said cover rearwardly and inwardly with respect to said rear casing section for tight engagement of said cover with the front and side edges of said rear casing section.

HAROLD L. MEKELBURG.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,368,619 Soderberg Feb. 6, 1945 1,906,669 Thomas, Jr May 2, 1933 1,528,473 Edwards Mar. 3, 1925 1,471,340 Knight Oct. 23, 1923 1,660,548 Crowell Feb. 28, 1928 2,108,888 Furnas et a1 Feb. 22, 1938 FOREIGN PATENTS Number Country Date 231,441 German Feb. 21, 1911 

